This invention relates generally to cancer and, more specifically, to biomarkers that can be used to diagnose or prognose cancer.
Cancer remains a major public health problem that profoundly affects the more than 1 million people diagnosed each year, as well as their families and friends. As our Nation's population grows and ages, more people will get cancer. The use of screening tests to detect cancers early often leads to more effective treatment with fewer side effects. Patients whose cancers are found early also are less likely to die from these cancers than are those whose cancers are not found until symptoms appear.
One type of cancer screening test involves the detection of a biomarker, such as a tumor marker, in a fluid or tissue obtained from a patient. Tumor markers are substances produced by cancer cells that are not typically produced by normal cells. These substances generally can be detected in the body fluids or tissues of patients with cancer. Unfortunately, some tumor markers also can be detected in significant amounts in the body fluids or tissues of people who do not have cancer, making certain markers less reliable for diagnosis. Nevertheless, tumor markers remain an important tool for diagnosing cancer.
Another important use for tumor markers is for monitoring patients being treated for advanced cancer. Measuring tumor markers for this purpose can be less invasive, less time-consuming, as well as less expensive, than repeating chest x-rays, computed tomography (CT) scans, bone scans, or other complicated tests, to determine if a therapy is reducing the cancer.
A further important use for tumor markers is for determining a prognosis of survival of a cancer patient. Such prognostic methods can be used to identify surgically treated patients likely to experience cancer recurrence so that they can be offered additional therapeutic options. Biomarkers useful for prognosis of survival also can be especially effective for determining the risk of metastasis in patients who demonstrate no measurable metastasis at the time of examination or surgery. Knowledge of the likelihood of metastasis in a cancer patient can be an important factor in selecting a treatment option. For example, a cancer patient likely to experience metastasis may be advantageously treated using a modality that is particularly aggressive.
Thus, there exists a need for identification of biomarkers that can be used as diagnostic and prognostic indicators for cancer. The present invention satisfies this need and provides related advantages as well.